Copper leads can be welded to conductive metals using ultrasound technology. In particular, cross-sections greater than 0.5 mm2 can be joined with good pull-off values. Crimping during welding generally results in a weakening of the material and in defined weak points, hampering in particular the welding of cross-sections measuring 0.35 mm2 or less. The reduced pull-off forces make the use of such thin leads impracticable. And compacting prior to welding is only marginally helpful.
To help obtain a larger cross-section, open crimping sleeves are frequently used. The disadvantage here is that the quality of the connection is dependent on the orientation of the crimped geometry on the connecting plate, and the strength of the crimp is generally weakened by the ultrasonic energy, since the crimp sides are merely rolled and can open up again during crimping. Relative movements within the crimp can occur, which can also damage the crimp.